US Patent 8495429 Log message anomaly detection

One or more techniques and/or systems are disclosed for detecting anomalies in a message log. A log message is parsed from an unstructured text string to a structured form, comprising messages signature and parameter values. Structured log messages that contain a same parameter value of a same program variable are grouped together. One or more invariants for are identified from respective types of log message groups. Invariants are applied to log sequences of respective log types.